The invention relates to an apparatus and method for recovering and recycling refrigerant from an air conditioning unit.
Most modem air conditioning equipment employ one of several organic solvent compositions, commonly referred to as chlorofluorocarbon compounds (CFCs), as a working fluid (refrigerant). For various reasons, such as wearing of the seals in the air conditioning equipment""s compressor, the refrigerant in the equipment may eventually become contaminated with dirt, oil and/or moisture. These contaminants affect the efficiency of the equipment and may eventually lead to damage of the compressor and other components in the equipment. Thus, it is desirable to replace the refrigerant periodically to avoid damaging the equipment and to restore the equipment""s overall efficiency. Also, in the event of a failure of the equipment, it is typically required that the refrigerant be removed from the equipment prior to servicing.
Previously, the most common method of removing the refrigerant from the equipment was to vent the refrigerant into the atmosphere and to replace it with virgin refrigerant as required. However, problems exist with this method of removing the refrigerant. The release of CFC compounds into the atmosphere results in the depletion of the ozone layer therein. As the ozone layer is the principal filter in the atmosphere for removing the sun""s ultraviolet radiation, much concern has been expressed about its depletion as it is expected to lead to many problems. For example, it is expected that an upturn in related health problems such as skin cancer will occur. Accordingly, many governments are passing legislation restricting or prohibiting the use of and/or releases of CFC compounds into the atmosphere. These restrictions pose a serious problem to refrigeration equipment manufacturers and servicers who no longer can release CFC-type refrigerants into the atmosphere. Furthermore, replacing refrigerant which has been vented to the atmosphere is expensive and may be difficult to obtain.
Refrigerant recovery and recycling systems are described in, for example, U.S. Pat. Nos. 3,699,781; 4,285,206; 4,364,236; 4,805,416; 4,768,347; 4,809,520; 5,072,593; 5,245,840; 5,335,512; 4,809,520; 5,353,603; 5,617,731; and 5,934,091.
An apparatus for recovering and recycling refrigerant is provided. The apparatus includes a separation unit, a compressor, and a receiver tank. The separation unit is provided for condensing compressed refrigerant and for vaporizing contaminated refrigerant. The separation unit includes a multichamber structure having a high pressure region and a low pressure region. The high pressure region includes a high pressure inlet for providing compressed refrigerant vapor to the high pressure region, a high pressure outlet for removing condensed refrigerant from the high pressure region, and a compressor oil outlet for removing compressor oil from the high pressure region. The low pressure region includes a low pressure inlet for introducing contaminated refrigerant into the low pressure region, a low pressure outlet for removing vaporized refrigerant from the low pressure region, and a refrigerant oil outlet for removing refrigerant oil from the low pressure region. The compressor is provided for compressing refrigerant from the low pressure outlet of the separation unit to provide compressed refrigerant for feeding to the high pressure inlet of the separation unit. The receiver tank is provided for receiving condensed refrigerant from the high pressure outlet of the separation unit.
The apparatus preferably includes a manifold assembly. The manifold assembly is provided for controlling the flow of processing fluid through the apparatus. The manifold assembly includes several passageways for directing the flow of processing fluid. For example, the manifold assembly preferably includes two or more of the following lines: a contaminated refrigerant recovery line; a vaporized refrigerant line; a compressed refrigerant line; and a condensed refrigerant line. The contaminated refrigerant recovery line is provided for directing contaminated refrigerant into the low pressure region of the separation unit. The vaporized refrigerant line is provided for directing vaporized refrigerant from the low pressure region of the separation unit to the compressor. The compressed refrigerant line is provided for directing compressed refrigerant into the high pressure region of the separation unit. The condensed refrigerant line is provided for directing condensed refrigerant from the high pressure region of the separation unit to the receiver tank. Valves can be provided on each of these lines for directing flow through the lines. The valves are preferably solenoid valves and are preferably controlled by a microprocessor.
The apparatus for recovering and recycling refrigerant can include a filter for filtering the contaminated refrigerant prior to introduction into the separation unit. The filter preferably includes a magnet for attracting metallic particulates. In addition, the filter preferably includes a screen for obstructing the flow of particular sized particulates or fibers into the separation unit. Preferably, the filter including a magnet is provided upstream of any solenoid valves.
A method for recovering and recycling refrigerant is provided by the invention. The method can be implemented using the apparatus of the invention. The method can include steps of feeding contaminated refrigerant to the separation unit; compressing the vaporized refrigerant from the low pressure outlet of the separation unit to provide compressed refrigerant vapor; feeding the compressed refrigerant vapor to the high pressure inlet of the high pressure region of the separation unit; separating oil from the compressed refrigerant and recovering the oil in the separation unit; condensing the compressed refrigerant vapor to provide condensed refrigerant in the separation unit; and feeding the condensed refrigerant to the receiver tank.